Nothing in Biology Makes Sense…

February 21, 2009 at 3:40 pm (Articles, religion) (, , , , , , , , )

Nothing in Biology Makes Sense Except in the Light of Evolution.

These are the words of Theodosius Dobzhansky, one of the founding fathers of the quantitative study of evolution. He wrote an essay about why evolution is so important, and also discussed how he reconciled his Christian faith and the scientific theory of evolution.

The evidence for evolution is overwhelming, if you accept scientific reasoning. There is mathematically no way that evolution could not occur if just three things are true: more creatures are born than get to reproduce; they can vary in new ways; and that these variations are inherited. The first is trivially true as any look in the garden will show, as is the third: for example people take after their parents. The second is more difficult because although all individuals do vary, they mostly do so in an uncreative way by mixing up the traits of their parents. But it does occur: mutations are the source of these creative changes and it has been demonstrated many times that novel abilities (at the microscopic level) can arise.

There is a resurgence recently, particularly in America, to doubt evolution for religious reasons. However, this doesn’t have anything to do with the religion per se, but is a cultural phenomenon. Dobzhansky quite powerfully argues that to deny evolution on religious grounds is verging on blasphemous: it implies that the creator deliberately set out to deceive us. We have the ability to reason about the origins of fossils, or of finches in the Galapogos, and explain why they are there. There is no hole in the theory that has yet been found. To believe that this is some elaborate charade is absurd.

Dobzhansky believed in creation: that god created the world such that we would be here today.  It is a matter of philosophy whether this happened by divine will or by chance.  It is beyond science to answer the question of whether we were “created” in this way, or arose by chance, because there is only one universe from which to draw evidence. But in this Universe, we have surely evolved, and this is not evidencef or or against God in the slightest.

Check out his essay for details of the above discussion.


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The history of mathematics…

July 31, 2008 at 4:30 pm (science) (, , , )

“The history of mathematics is a Markov Chain”.  This is a joke (probably not apparent to non-mathematicians!), but like the best jokes, is based in truth.

Because not everyone here knows what a Markov Chain is, I should explain.  A Markov Chain describes things that change in a way that has no memory.  What happens in the future doesn’t depend on what happened in the past.  Picture a drunk, staggering home after a night out.  Each step he takes is in a random direction.  He might recognise the local shop, and walk towards it – but if he gets lost, and finds the shop again, there is nothing to stop him making the same mistake twice and walking in circles – because he can’t remember where he’s been, but only where he is.

The joke says that mathematics reinvents the same concepts over and over – which is true of this concept.  It was independently invented in physics by Einstein for his description of Brownian Motion, and in mathematics by Andrey Markov in work on probability theory.

A post at Scienceblogs reminded me of this, and it is interesting because (as they argue well) all of Science is like this.  Scientists are not Historians, so we only remember what is important enough to get into textbooks.  If it doesn’t make it it – the next generation don’t know about it, and it becomes forgotten, doomed to be repeated again and again.

I wonder if the Internet will help us overcome this?  When (say) PhD students of 2050 do a literature search for some obscure gene, will they find information from now about it in databases and papers, and will that be of any use to them?  Can we use this to allow science to progress in useful directions, by remembering those that were failures?  Or will failures of the past be viewed as caused by ignorance or lack of equipment, that enlightened folk of “today” can deal with without problem?

Without it, Science will be doomed to proceed as a Drunkard’s Walk, lurching between discoveries on the same old path of failures.  We can easily explore the area around the pub like this, but it takes an awfully long time to stumble back home.

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